One of the biggest web sites in the world was briefly identified by two Microsoft security software products as being infected with malware. ZDNet UK reports that on Tuesday the programs, Microsoft Forefront and Microsoft Security Essentials, got an update that mistakenly tagged Google.com as being infected with the Blackhole exploit kit.

Because of the erroneous update, users of those software programs around the world posted word on Microsoft support forums that the applications were not allowing them to access Google.com. In a few hours, yet another update was sent out to both programs. In a post on the Sans Institute web site, the security group said, "As of 20:11 GMT-5 Feb 14 2012, we received confirmation from Microsoft stating that this problem is a false positive and will be corrected in the update 1.119.1986.0 or higher for the antivirus."

The Blackhole exploit kit was first discovered back in 2010. Developed by Russian hackers. the exploit kit can infect web sites and then transmit malware to the hard drives of PC users who visit the corrupted sites. It's currently unknown why the two Microsoft security programs would have flagged Google.com as having Blackhole installed. So far Microsoft has yet to comment on the issue.